Hynix 4GB 2Rx4 PC2-5300P-555-12 server memory modules, specifically designed for high-performance computing environments. These DDR2 Registered ECC modules carry the model number HYMP151P72CP4-Y5 AB and are IBM branded with part number 77P6500. Each stick provides 4GB of capacity, operating at 667MHz to ensure reliable data processing and system stability. The modules feature a 240-pin form factor and are built with high-quality components, making them an ideal choice for upgrading or maintaining legacy server systems that require specific IBM-compatible hardware. Sold as a set of four for a total of 16GB.